For liquid electro-photographic (LEP) printers, such as HP Indigo presses, liquid ink (Electrolnk™) contains a colorant that is used to produce color images. In general, LEP printers use a BID (binary ink development) unit to transfer ink onto an organophotoconductor (OPC) drum. One of the reliability issues that limit the usable life of the BID, as well as other components in contact with the ink, is the accumulation of “sludge” (concentrated ink paste) onto one or more surfaces of the BID. In particular, sludge accumulates on walls of the tray or surfaces of other parts in the BID, which causes leaking of the ink from the BID unit and other functional failures. It should also be noted that sludge causes problems in other areas of the LEP printers such as in ink tanks, ink flowing pipes, and other structures that contact the ink. Therefore, a need exists in the art to overcome the problems associated with sludge.